<< >> NASA ASRS Report 518554, July 2001

A B737-300 has in-flight autoplt problem and advises maintenance. Maintenance requests engaging previous deferred 'B' autoplt which trips off.

Attributes
ACN	518554
Time
Date	200107
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz.airport
State Reference	US
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : o90.tracon artcc : lfff.artcc
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	maintenance : lead technician
Qualification	technician : airframe technician : powerplant
Experience	maintenance lead technician : 2 maintenance technician : 12
ASRS Report	518554
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper documentation maintenance problem : improper maintenance maintenance problem : non compliance with mel non adherence : published procedure non adherence : far
Independent Detector	aircraft equipment other aircraft equipment : auto pilot disconnect other flight crewa other flight crewb
Resolutory Action	flight crew : declared emergency
Consequence	other
Factors
Maintenance	performance deficiency : non compliance with legal requirements performance deficiency : testing
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft Maintenance Human Performance
Primary Problem	Maintenance Human Performance

Narrative:

I received a call from a B737-300 in-flight with an 'a' autoplt problem. In trying to get more information from the crew on the problem, I reviewed the deferred items and the 'B' autoplt was deferred inoperative for failing a ground test. I had the crew engage the 'B' autoplt to see if, perhaps, the mechanic had deferred the wrong autoplt. The crew did engage the 'B' autoplt and it operated normally for the duration of the call. I did receive a message about 10 mins later that the 'B' autoplt disengaged. The aircraft, on approach, had a control problem and declared an emergency. In my opinion, the autoplt problems had nothing to do with the control problem. Autoplt, both a and B, were ground checked in ZZZ and passed. An inspection of flight control checks with no defects.

Related reports:

• A B737-300 depressurized in-flight and 3 passenger emergency...

	Enter your search terms Submit search form
	Web www.37000feet.com

Original NASA ASRS Text

Title: A B737-300 HAS INFLT AUTOPLT PROB AND ADVISES MAINT. MAINT REQUESTS ENGAGING PREVIOUS DEFERRED 'B' AUTOPLT WHICH TRIPS OFF.

Narrative: I RECEIVED A CALL FROM A B737-300 INFLT WITH AN 'A' AUTOPLT PROB. IN TRYING TO GET MORE INFO FROM THE CREW ON THE PROB, I REVIEWED THE DEFERRED ITEMS AND THE 'B' AUTOPLT WAS DEFERRED INOP FOR FAILING A GND TEST. I HAD THE CREW ENGAGE THE 'B' AUTOPLT TO SEE IF, PERHAPS, THE MECH HAD DEFERRED THE WRONG AUTOPLT. THE CREW DID ENGAGE THE 'B' AUTOPLT AND IT OPERATED NORMALLY FOR THE DURATION OF THE CALL. I DID RECEIVE A MESSAGE ABOUT 10 MINS LATER THAT THE 'B' AUTOPLT DISENGAGED. THE ACFT, ON APCH, HAD A CTL PROB AND DECLARED AN EMER. IN MY OPINION, THE AUTOPLT PROBS HAD NOTHING TO DO WITH THE CTL PROB. AUTOPLT, BOTH A AND B, WERE GND CHKED IN ZZZ AND PASSED. AN INSPECTION OF FLT CTL CHKS WITH NO DEFECTS.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.